Quantitative Calculation and Prediction of Spectroscopic Properties of Thulium-doped Germanate Laser Glass

Abstract： Rare-earth-doped laser glass is the key medium of fiber lasers.However， how to predict the spectroscop• ic properties quantitatively remains a challenge to accelerate the development of high-performance laser glass.Here we regard the nearest-neighboring congruently melting compound(CMC) as the component and structural "motif" of glass based on the phase diagram model and apply it to the Tm 3+ -doped binary germanate laser glass systems.The ex• perimental properties of Tm 3+ -doped glassy CMCs are utilized to calculate and predict the physical and spectroscopic properties， such as density， refractive index， effective linewidth， absorption/emission cross-sections， radiation life• time， etc. ， of germanate laser glass by utilizing the leverage rule.The results illustrate that the predicted physical and spectroscopic properties are in good agreement with the experimental values， with the maximum absolute errors of less than 4. 61% and 9. 66%， respectively.Moreover， the phase diagram approach can capture the trends of physi• cal and spectroscopic properties as a function of composition， including the linearly or germanate-anomaly composi• tional dependence， which provides an opportunity to decipher the composition-structure-property relationships of la• ser glass.This study is expected to shed light on the property prediction and composition design of laser glass.